As mentioned earlier, it is misleading to refer to lax vowels as short vowels because some of the opener lax vowels are actually quite long. A more important durational rule is the following:
PRE-FORTIS CLIPPING: Regardless of phonemic classification, vowels (and sonorant consonants) are shortened before fortis obstruents in the same syllable.
That is, the voiced part of the syllable rhyme is short when the coda is fortis. We work out the details below:
1. Vowels in open syllables (this of course only affects tense vowels), e.g. see /siː/ and shoe /ʃuː/ are almost twice as long as vowels before fortis consonants, e.g. seat /siːt/ and shoot /ʃuːt/.
2. Before lenis obstruents, vowels are almost twice as long as when they are before fortis consonants. The lenis obstruents are, of course, /b, d, g, v ð, z, ʒ/. (What are the fortis obstruents?) As we will see in a following chapter, the lenis obstruents are frequently devoiced, so that to a large extent the distinction between /biːd/ and /biːt/ is phonetically expressed by the fact that vowel in bead is about twice as long as the vowel in beat. In spite of the fact that the rule is given as a ‘clipping’ rule, making the vowels too short in non-clipped contexts is one of the most common mistakes of Dutch students. Most students assume that they’re exaggerating the length but it’s better to overcompensate and make the vowel too long at first, than to not make any distinction at all. On the other hand, when GA /iː/ and /uː/ occur before fortis codas, Dutch learners often make these vowels too long, because they replace them with marginal AN /iː/ and /uː/ of analyse and rouge. So be careful to pronounce words like GA geese, goose, meet, moot, belief, aloof, leash, louche, keep, coop, leach, mooch, teak with shortish vowels, perhaps using the duration of AN /y/ as in Truus as a reference.
3. When the vowel is followed by a sonorant (GA /m, n, ŋ; l, r), the rule applies to the combination of vowel+sonorant. That is, /ɛn/ in send is about twice as long as /ɛn/ in cent. Particularly in the case of lax vowels, it is usually better to apply your lengthening efforts to the sonorant rather than the vowel. That is, say [senːːːd] rather than [seːːːnd].
Some minimal pairs are given below. They include cases with just a vowel before the final obstruent and cases with a vowel-plus-sonorant combination before the obstruent. In each case, the vowel (plus sonorant) in the second word is almost twice as long as the vowel (plus sonorant) in the first. The pairs in the first two lines of each set of four have the ‘clipped’ word first, and the pairs in the second two lines have the ‘clipped’ word in second position. Listen to the duration of the voiced portions in the four pairs below. Then try pronouncing them in the same way for the other pairs underneath.
Listen to the following triplets. The first two have longish vowels (and sonorants) while the third is clipped.
Now try these yourself.